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Neoadjuvant Dalpiciclib + AI → SHR-A1811 for HR+/HER2-Low Breast Cancer (TD-DASHER-01)

8 de junio de 2026 actualizado por: Tang-Du Hospital

Dalpiciclib Combined With Aromatase Inhibitor (AI) Followed by SHR-A1811 as Neoadjuvant Therapy in Patients With Intermediate-to-High Risk HR+/HER2-Low Breast Cancer: A Phase II Exploratory Study

This is a phase II, single-arm, prospective exploratory study to evaluate the efficacy and safety of neoadjuvant dalpiciclib (a CDK4/6 inhibitor) plus an aromatase inhibitor (AI) followed by SHR-A1811 (an anti-HER2 antibody-drug conjugate) in patients with intermediate-to-high risk, hormone receptor-positive (HR+), HER2-low breast cancer. Patients will receive dalpiciclib (125 mg orally once daily, days 1-21, every 4 weeks) plus AI (anastrozole 1 mg, letrozole 2.5 mg, or exemestane 25 mg once daily) for 4 cycles, followed by SHR-A1811 (4.8 mg/kg intravenously every 3 weeks) for 4 cycles. The primary endpoint is objective response rate (ORR) per RECIST 1.1. Secondary endpoints include pathological complete response (pCR), breast-conserving surgery rate, event-free survival (EFS), change in Ki-67 index, and safety. A total of 20 participants will be enrolled.

Descripción general del estudio

Descripción detallada

This is a single-arm, open-label, phase II exploratory trial conducted at a single center (Second Affiliated Hospital of Air Force Medical University, China). The study aims to investigate the activity and safety of dalpiciclib plus an aromatase inhibitor (AI) followed by the HER2-directed antibody-drug conjugate (ADC) SHR-A1811 as neoadjuvant therapy for patients with intermediate-to-high risk, hormone receptor-positive (HR+), HER2-low breast cancer.

Preclinical evidence suggests that CDK4/6 inhibition may enhance the immunogenic cell death induced by ADCs and overcome tumor heterogeneity. Dalpiciclib is a selective CDK4/6 inhibitor with a distinct piperidine structure associated with low hepatotoxicity and minimal gastrointestinal side effects. SHR-A1811 is a HER2-targeted ADC composed of a humanized anti-HER2 IgG1 monoclonal antibody (based on trastuzumab sequence), a cleavable maleimide tetrapeptide (GGFG) linker, and a DNA topoisomerase I inhibitor (SHR169265). It demonstrates bystander killing of HER2-low cells. The 4-cycle induction with dalpiciclib plus AI prior to SHR-A1811 is designed to reduce tumor proliferation and potentially prime the tumor microenvironment before ADC administration.

Treatment administration

  • Dalpiciclib: 125 mg orally once daily on days 1-21 of each 28-day cycle (4 cycles total). Patients are instructed to take the tablet at approximately the same time each day, on an empty stomach (≥1 hour before or after food). Missed doses are not supplemented; vomiting within a short time after intake does not trigger a replacement dose. Interruption for >21 consecutive days requires study discontinuation. Dose reductions follow a stepwise scheme: 125 mg → 100 mg → 75 mg.
  • Aromatase inhibitor (AI): Investigator's choice of anastrozole 1 mg daily, letrozole 2.5 mg daily, or exemestane 25 mg daily, taken continuously during the first 4 cycles. Premenopausal patients (mandatory) and perimenopausal patients (at investigator's discretion) receive concomitant LHRH agonists (e.g., goserelin or leuprolide).
  • SHR-A1811: 4.8 mg/kg intravenously over a standard infusion duration on day 1 of each 21-day cycle (4 cycles total). The dose is recalculated based on body weight measured immediately before each cycle. If weight change from baseline is <10%, no dose adjustment is required. Dose reductions follow a 4.8 → 3.2 mg/kg step. Infusion-related reactions are managed according to a predefined algorithm (slow infusion, antihistamines, corticosteroids, or permanent discontinuation for grade ≥3 reactions).

Tipo de estudio

Intervencionista

Inscripción (Estimado)

20

Fase

  • Fase 2

Criterios de participación

Los investigadores buscan personas que se ajusten a una determinada descripción, denominada criterio de elegibilidad. Algunos ejemplos de estos criterios son el estado de salud general de una persona o tratamientos previos.

Criterio de elegibilidad

Edades elegibles para estudiar

  • Adulto
  • Adulto Mayor

Acepta Voluntarios Saludables

No

Descripción

Inclusion Criteria:

  1. Age ≥18 and ≤70 years
  2. Histologically confirmed invasive breast cancer, HR+ (ER ≥1% and/or PR ≥1%) and HER2-low (IHC 1+ or IHC 2+/ISH-)
  3. No prior systemic anti-tumor therapy for breast cancer
  4. Stage II-III (T1cN1-2M0, T2-4N0-2M0) per AJCC 8th edition
  5. At least one of the following intermediate-to-high risk factors:

    • Axillary lymph node involvement ≥1
    • Tumor size≥2 cm
    • Grade 3 tumor
    • Ki-67 ≥20%
  6. At least one measurable lesion per RECIST 1.1
  7. ECOG PS 0-1
  8. Adequate organ function (ANC ≥1.5×10⁹/L, platelets ≥100×10⁹/L, Hb ≥90 g/L, TBIL ≤1.5×ULN, ALT/AST ≤2.5×ULN, Cr ≤1.5×ULN or CrCl ≥60 mL/min, LVEF ≥50%, QTcF ≤470 ms in females, DLCO ≥50% predicted
  9. Negative pregnancy test (for women of childbearing potential) and agreement to use adequate contraception during and for 6 months after treatment
  10. Willing and able to provide informed consent and comply with study procedures

Exclusion Criteria:

  1. Non-pathologically confirmed breast cancer
  2. Bilateral, inflammatory, or occult breast cancer
  3. Prior anticancer therapy (chemotherapy, radiotherapy, targeted therapy, endocrine therapy, etc.)
  4. Concurrent use of other anticancer treatments
  5. Other malignancy within 5 years (except cured basal cell carcinoma or cervical carcinoma in situ)
  6. Participation in another interventional clinical trial within 4 weeks prior to first dose
  7. Use of immunosuppressive agents or systemic corticosteroids (>10 mg/day prednisone or equivalent) within 2 weeks prior to first dose
  8. Live or attenuated vaccine within 4 weeks prior to first dose
  9. Major surgery unrelated to breast cancer within 4 weeks prior to first dose
  10. Active or history of autoimmune disease requiring systemic treatment
  11. Known immunodeficiency (e.g., HIV positivity) or history of organ transplantation
  12. Uncontrolled or significant cardiovascular disease (e.g., NYHA class III/IV heart failure, myocardial infarction, unstable angina, arrhythmia requiring treatment, QTcF >470 ms, uncontrolled hypertension)
  13. Known or suspected interstitial lung disease (ILD) or significant pre-existing pulmonary disease
  14. Active hepatitis B (HBsAg positive and HBV DNA ≥500 IU/mL) or hepatitis C (HCV RNA above ULN), cirrhosis, or uncontrolled severe infection
  15. Known bleeding or thrombotic tendency
  16. Allergy or contraindication to any study drug or excipient
  17. Pregnancy, breastfeeding, or positive pregnancy test at baseline
  18. Any concurrent condition that may compromise patient safety or study compliance (e.g., uncontrolled hypertension, severe diabetes, active infection)
  19. History of neurological or psychiatric disorders (e.g., epilepsy, dementia) or any condition deemed unsuitable by the investigator.

Plan de estudios

Esta sección proporciona detalles del plan de estudio, incluido cómo está diseñado el estudio y qué mide el estudio.

¿Cómo está diseñado el estudio?

Detalles de diseño

  • Propósito principal: Tratamiento
  • Asignación: N / A
  • Modelo Intervencionista: Asignación de un solo grupo
  • Enmascaramiento: Ninguno (etiqueta abierta)

Armas e Intervenciones

Grupo de participantes/brazo
Intervención / Tratamiento
Experimental: Dalpiciclib + Aromatase Inhibitor followed by SHR-A1811
CDK4/6 inhibitor, 125 mg oral tablet, taken once daily on days 1-21 of each 28 day cycle for 4 cycles.
Includes anastrozole 1 mg/day, letrozole 2.5 mg/day, or exemestane 25 mg/day, administered orally once daily for 4 cycles.
Anti-HER2 antibody-drug conjugate (ADC), 4.8 mg/kg intravenous infusion once every 3 weeks for 4 cycles

¿Qué mide el estudio?

Medidas de resultado primarias

Medida de resultado
Medida Descripción
Periodo de tiempo
Objective Response Rate (ORR)
Periodo de tiempo: After completion of 8 cycles of neoadjuvant therapy (Cycles 1-4: 28 days/cycle; Cycles 5-8: 21 days/cycle), within 4 weeks prior to surgery
Proportion of patients achieving complete response (CR) or partial response (PR) per RECIST 1.1
After completion of 8 cycles of neoadjuvant therapy (Cycles 1-4: 28 days/cycle; Cycles 5-8: 21 days/cycle), within 4 weeks prior to surgery

Medidas de resultado secundarias

Medida de resultado
Medida Descripción
Periodo de tiempo
Breast-Conserving Surgery Rate
Periodo de tiempo: At the time of surgery
Proportion of participants who undergo breast-conserving surgery (BCS) after neoadjuvant therapy. BCS is defined as surgical resection of the primary tumor with negative margins while preserving the breast contour, as opposed to total mastectomy.
At the time of surgery
Event-Free Survival (EFS)
Periodo de tiempo: From enrollment up to 5 years after last patient enrollment (assessed every 3 months during the first year, then every 6 months thereafter
EFS is defined as the time from enrollment to the first occurrence of any of the following events: disease progression (local, regional, or distant) during neoadjuvant therapy, disease recurrence after surgery (local, regional, or distant), contralateral breast cancer, any secondary malignancy, or death from any cause. Participants without an event at the time of last follow-up are censored.
From enrollment up to 5 years after last patient enrollment (assessed every 3 months during the first year, then every 6 months thereafter
Incidence of Adverse Events (AEs) and Serious Adverse Events (SAEs)
Periodo de tiempo: From signing of informed consent through 30 days after the last dose of study drug, or until initiation of new anticancer therapy, whichever occurs first.
Safety outcomes include: incidence of any AE, incidence of grade ≥3 AE (per NCI-CTCAE version 6.0), incidence of SAEs, incidence of AE leading to treatment discontinuation or dose modification, and incidence of AE by system organ class and preferred term. Laboratory abnormalities, vital signs, ECG parameters (QTcF, heart rate), and left ventricular ejection fraction (LVEF) are also summarized.
From signing of informed consent through 30 days after the last dose of study drug, or until initiation of new anticancer therapy, whichever occurs first.
Pathological Complete Response Rate (pCR): ypT0-is/ypN0
Periodo de tiempo: At the time of surgery, performed within 4 weeks after completion of 8 cycles of neoadjuvant therapy (Cycles 1-4: 28 days/cycle; Cycles 5-8: 21 days/cycle).
pCR is defined as absence of invasive carcinoma in the breast primary tumor (ypT0/is) and absence of tumor cells in axillary lymph nodes (ypN0) on pathological examination of the surgical specimen after neoadjuvant therapy. Presence of ductal carcinoma in situ (DCIS) alone is allowed.
At the time of surgery, performed within 4 weeks after completion of 8 cycles of neoadjuvant therapy (Cycles 1-4: 28 days/cycle; Cycles 5-8: 21 days/cycle).
Ki-67 Index Change
Periodo de tiempo: Baseline (pre-treatment core needle biopsy) and at surgery (post-neoadjuvant surgical specimen).
Ki-67 index is measured by immunohistochemistry (IHC) as the percentage of tumor cells with positive nuclear staining. The scale is the Ki-67 proliferation index, which ranges from 0% (minimum) to 100% (maximum). Higher scores indicate a worse outcome (higher proliferative activity). The change is calculated as Ki-67 index at surgery minus Ki-67 index at baseline. A negative value (reduction) indicates a better outcome (decreased proliferation), while a positive value (increase) indicates a worse outcome.
Baseline (pre-treatment core needle biopsy) and at surgery (post-neoadjuvant surgical specimen).

Colaboradores e Investigadores

Aquí es donde encontrará personas y organizaciones involucradas en este estudio.

Patrocinador

Fechas de registro del estudio

Estas fechas rastrean el progreso del registro del estudio y los envíos de resultados resumidos a ClinicalTrials.gov. Los registros del estudio y los resultados informados son revisados ​​por la Biblioteca Nacional de Medicina (NLM) para asegurarse de que cumplan con los estándares de control de calidad específicos antes de publicarlos en el sitio web público.

Fechas importantes del estudio

Inicio del estudio (Estimado)

1 de junio de 2026

Finalización primaria (Estimado)

1 de junio de 2028

Finalización del estudio (Estimado)

1 de enero de 2029

Fechas de registro del estudio

Enviado por primera vez

24 de mayo de 2026

Primero enviado que cumplió con los criterios de control de calidad

24 de mayo de 2026

Publicado por primera vez (Actual)

1 de junio de 2026

Actualizaciones de registros de estudio

Última actualización publicada (Actual)

11 de junio de 2026

Última actualización enviada que cumplió con los criterios de control de calidad

8 de junio de 2026

Última verificación

1 de junio de 2026

Más información

Términos relacionados con este estudio

Plan de datos de participantes individuales (IPD)

¿Planea compartir datos de participantes individuales (IPD)?

NO

Descripción del plan IPD

The informed consent form signed by participants does not include provisions for sharing individual participant data with external researchers.

Información sobre medicamentos y dispositivos, documentos del estudio

Estudia un producto farmacéutico regulado por la FDA de EE. UU.

No

Estudia un producto de dispositivo regulado por la FDA de EE. UU.

No

Esta información se obtuvo directamente del sitio web clinicaltrials.gov sin cambios. Si tiene alguna solicitud para cambiar, eliminar o actualizar los detalles de su estudio, comuníquese con register@clinicaltrials.gov. Tan pronto como se implemente un cambio en clinicaltrials.gov, también se actualizará automáticamente en nuestro sitio web. .

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